The invention relates to a process for the production of methanol and a catalyst composition for said process.
More particularly the invention relates to a process for the production of methanol by reaction of carbon monoxide with hydrogen in the presence of a catalytic system in the liquid phase derived from at least a salt containing a cation of an element of group VIII of the Periodic Table of the Elements and an alcoholate.
A process for the production of methanol is described in specification U.S. Pat. No. 4,619,946 comprising reacting at relatively low temperature carbon monoxide with hydrogen in the presence of a catalytic system derived from sodium hydride, sodium alcoholate and acetate of nickel, palladium or cobalt. The alcoholate applied is preferably a lower alkanolate having 1-6 carbon atoms and more preferably a tert-alkanolate, while as metal salt nickel acetate is preferably used.
The catalyst is subjected to a conditioning or activating step for a prolonged time with a gaseous mixture comprising carbon monoxide and hydrogen at such an elevated temperature and elevated pressure that a substantial amount of carbon monoxide and hydrogen is consumed for this conditioning.
Also in specification U.S. Pat. No. 4,614,749 a process is disclosed for the production of methanol at relatively low temperature by reaction of carbon monoxide with hydrogen in the presence of a slurry catalyst system resulting from combination of
a complex reducing agent comprising sodium hydride-alcohol and an acetate of nickel, palladium or cobalt, and PA1 a carbonyl complex of one of the group VI metals. PA1 component (a): a substantially dry nickel formate, PA1 component (b): water in a predetermined amount in relation to the nickel formate amount, and PA1 component (c): an alcoholate derived from an alkali metal or from an alkaline earth metal.
The alcohol to be applied is preferably selected from lower alkanols, having from 1 to 6 carbon atoms and more preferably tertiary amyl alcohol.
Another process for the production of methanol is described in published Japanese patent application No. 56-169,634. This process comprises reacting carbon monoxide and hydrogen in the presence of a catalyst comprising a nickel compound and a metal alkoxide, in the liquid phase at temperatures of 200.degree. C. or lower. More preferably an alkali metal alkoxide might be used. The catalyst to be used for this process may be prepared by mixing a nickel compound with an alkali metal alkoxide, while it is preferable to use an organic diluent which is liquid under the preparation and use conditions of the catalyst system.
More particularly the teachings of this Japanese patent application instruct a person skilled in the art, that a high reaction rate may be reached by preparing the catalyst system with the use of a substantially alcohol free organic diluent and that it is desirable that an alcohol be not present in the reaction system at the commencement of the reaction.
Moreover from this Japanese patent application and especially from its example 2, it clearly appears that at low temperature only small amounts of methanol are produced in favour of production of methyl formate in large amounts.
Although improvements in the performances of the catalyst systems as described hereinbefore, could be reached as compared to those used in the conventional methanol manufacturing processes, requiring severe conditions, the still growing demand for cheaper methanol as starting material for a still increasing area of chemical syntheses evoked continuing research efforts for a further improved methanol manufacturing process as compared to the currently operated high pressure processes.
With the term improved methanol manufacturing process is meant a process utilizing a catalyst having enhanced activity at low temperatures, and retaining its activity for a long time under economically more attractive operating conditions.
An object of the present invention is therefore to provide such an improved manufacturing process for methanol. Another object of the present invention is to provide an improved catalyst system therefor.